Reset property tree indices when layer is removed from layer tree

cc/trees/property_tree.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_TREES_PROPERTY_TREE_H_
 #define CC_TREES_PROPERTY_TREE_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 123 matching lines @@
 typedef TreeNode<float> OpacityNode;
 
 template <typename T>
 class CC_EXPORT PropertyTree {
  public:
   PropertyTree();
   virtual ~PropertyTree();
 
   int Insert(const T& tree_node, int parent_id);
 
-  T* Node(int i) { return i > -1 ? &nodes_[i] : nullptr; }
-  const T* Node(int i) const { return i > -1 ? &nodes_[i] : nullptr; }
+  T* Node(int i) {
+    // TODO(vollick): remove this.
+    CHECK(i < static_cast<int>(nodes_.size()));
+    return i > -1 ? &nodes_[i] : nullptr;
+  }
+  const T* Node(int i) const {
+    // TODO(vollick): remove this.
+    CHECK(i < static_cast<int>(nodes_.size()));
+    return i > -1 ? &nodes_[i] : nullptr;
+  }
 
   T* parent(const T* t) { return Node(t->parent_id); }
   const T* parent(const T* t) const { return Node(t->parent_id); }
 
   T* back() { return size() ? &nodes_[nodes_.size() - 1] : nullptr; }
   const T* back() const {
     return size() ? &nodes_[nodes_.size() - 1] : nullptr;
   }
 
   void clear();
@@ skipping 83 matching lines @@
 class CC_EXPORT OpacityTree final : public PropertyTree<OpacityNode> {};
 
 class CC_EXPORT PropertyTrees final {
  public:
   PropertyTrees();
 
   TransformTree transform_tree;
   OpacityTree opacity_tree;
   ClipTree clip_tree;
   bool needs_rebuild;
+  int sequence_number;
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_PROPERTY_TREE_H_